v. t.
v. i. To grind or strike the teeth together. [ 1913 Webster ]
There they him laid,
Gnashing for anguish, and despite, and shame. Milton. [ 1913 Webster ]
adv. With gnashing. [ 1913 Webster ]
a. [ Etymol. uncertain. ] Firm; stiff; hard; also, chilly. [ Prov. Eng. ] Halliwell. [ 1913 Webster ]